Speedy IIF Will Get There Faster
May 19, 2010SECOND UPDATE: Launch has been delayed a second time. The United Launch Alliance (ULA) Delta IV launch vehicle is set to make another launch attempt on Monday night, following the telemetry signal issue which caused the scrub during Friday’s countdown, along with a late delay to Sunday’s rearranged launch. With the GPS IIF SV-1 spacecraft — the first of a new generation of GPS satellites for the US Air Force — riding as the passenger, the Delta IV’s 18 minute launch window at Cape Canaveral opens at 11:13 p.m. Eastern on Monday night.
UPDATE: The launch attempt of the United Launch Alliance Delta IV with the Air Force's Global Positioning System IIF-SV1 satellite (GPS IIF-SV1) has been rescheduled for May 21. During normal processing for launch, mission managers determined a piece of ground support equipment used to control one of the swing arms on the Fixed Umbilical Tower was not operating correctly and needed replacing. Replacing this GSE component will add one day to launch processing. The Delta IV rocket and GPS IIF-SV1 satellite are safe and secure at this time. The launch is rescheduled for Friday, May 21, with a launch window of 11:25 - 11:43 p.m. EDT (03:25 – 03:43 UTC on May 22).
Just before midnight on Thursday, May 20, the first of a new generation has a date with destiny on the Cape Canaveral launch pad. GPS spacecraft IIF-1 has a launch window extending from 11:29 to 11:48 p.m., Eastern daylight time. It’s in a hurry. Instead of taking several days to reach its orbital slot, the new satellite will make the journey in three-and-a-half hours.
IIF-1 catches its breathless ride aboard a Delta 4 rocket from the United Launch Alliance, a joint venture of Lockheed Martin and Boeing, formed in late 2006.
Earlier GPS satellites rode on smaller Delta 2 rockets that, although very reliable, did not possess the oomph to place space vehicles directly into the orbiting constellation, 11,000 miles high. Delta 2s put satellites into highly elliptical orbits looping from as low as 100 miles above Earth at perigee to the 11,000-mile apogee. At a strategic point, a solid-fuel kick motor attached to the satellites pushed them into position for circular orbit on high.
Like Space-Age William Tells, the more powerful Delta 4 will shoot the IIFs directly into their destination slots. Future IIF launches may also use Atlas 5 rockets, similarly endowed. The next one, GPS IIF-2, could rise aboard an Atlas 5 as early as November this year.
The IIF generation, manufactured by Boeing, will broadcast the new civil L5 signal. IIF satellites have a longer design life of 12 years, and faster processors with more memory. A total of 12 IIF satellites will make their contribution to getting the new L2C and L5 signals closer to operational capability, before the GPS III generation takes over.
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